Air filtering device

ABSTRACT

An air filtering device including a circular plate, plurality of fan blades fixedly attached to the circular plate, the fan blades extending downwardly from the lower surface of the circular plate; a filter frame having an air permeable cylindrical inner wall, having an upper wall, having a lower wall, and having an air permeable cylindrical outer wall, the air permeable cylindrical inner wall, the air permeable cylindrical outer wall, the upper wall and the lower wall defining a cylindrical filtering media containing space; air filtering media extending annularly around the air permeable cylindrical inner wall within the cylindrical filtering media containing space; and, filter frame attaching means attaching the filter frame so that it extends annularly around the outer edges of the fan blades.

[0001] The present application is a continuation-in-part of U.S. Ser.No. 08/953,598, filed Oct. 17, 1997, by Paul Fiacco, and entitled AIRFILTERING DEVICE.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to air filters. In particular, thisinvention relates to air filters incorporating filtering media and acentrifugal fan, the centrifugal fan preferably being attachable to therotor plate of a common ceiling fan. The invention also relates to anindustrial embodiment attachable to a rotary motor.

[0004] 2. Description of the Related Art

[0005] Air in homes or in business workplaces typically includes acolloid suspension of smoke particles, plant pollens, mold spores, anddust particles. Pollen and mold spores suspended in the air of a home ora workplace are common allergens which may cause sinusitis or hayfever,and other respiratory ailments. Dust suspended in the air may be harmfulto persons in a home or workplace who have emphysema or asthma.Additionally, airborne smoke and dust tends to discolor and soil itemsin a home or workplace such as curtains and furniture. In the workplace,the dangers of pollutants in the indoor environment are oftentimes moreharmful. For instance, the fumes emitted from cleaning solvents,hydrocarbons, acids and paint may cause serious long term health risks.Thus, it is widely seen as desirable to create home and workplaceenvironments whose air is substantially free of airborne smoke, pollen,mold spores, dust and other harmful pollutants.

[0006] Several types of apparatus for cleaning and filtering air withina home or workplace are known. Many have disadvantages. For example,free standing electric air cleaning machines, typically incorporating anair impeller and a filtering medium mounted in the path of air flow,take up useable space within a room and typically create undesirablebackground noise. Another air filtering device having disadvantages is acarbon filter or an electrostatic air filter which is installable as anauxiliary element of a building's central air and heating system. Suchsystems are mechanically complex, and are expensive to construct,maintain, and operate.

[0007] The instant inventive air filtering device overcomes suchdisadvantages, among others, by providing a mechanically simple airfilter which is economical to construct and operate, which takes upvirtually no living or working space of a home or workplace, and whichcreates virtually no background noise. Such benefits are obtainedthrough the provision of a centrifugal fan having a filtering mediaattached thereto and disposed therearound, the centrifugal fan andfiltering media assembly being attachable to and rotatable by the rotorplate of a common ceiling fan, such ceiling fan having its fan bladesremoved. In another embodiment, the air filtering media is disposed atthe periphery of a plate. The filtering media is secured in acompartment defined between the plate and a cover. Additionally, alarger, industrial embodiment may be attached to and rotatable by a morepowerful rotary motor.

[0008] Prior Art Patents

[0009] U.S. Pat. No. 4,849,862 issued Jul. 18, 1989, to Diskin, et al.,discloses a ceiling suspended air purifying light fixture.

[0010] U.S. Pat. No. 4,750,863 issued Jun. 14, 1988, to Scogginsdiscloses a fan shroud filter.

[0011] U.S. Pat. No. 4,450,756 issued May 29, 1984, to Kling discloses afume exhaust device.

[0012] U.S. Pat. No. 4,840,650 issued Jun. 20, 1989, to Mathemediscloses a ceiling fan filter.

[0013] U.S. Pat. No. 4,422,824 issued Jun. 27, 1983, to Eisenhardtdiscloses a germ killing ceiling fan.

[0014] U.S. Pat. No. 4,790,863 issued Dec. 13, 1988, to Nobirakidiscloses an air cleaner incorporating a centrifugal fan.

[0015] U.S. Pat. No. 5,443,625 issued Aug. 22, 1995, to Schafflhausendiscloses an air filtering fixture.

[0016] U.S. Pat. No. 4,676,721 issued Jun. 30, 1987, to Hardee disclosesaceiling fan air cleaner.

[0017] None of the above disclosed patents disclose, teach or describethe novel, inventive, useful and unique characteristics and features ofthe present inventive air filtering device.

BRIEF SUMMARY OF THE INVENTION

[0018] The present inventive air filtering device comprises an uppercircular plate, preferably between three and four feet in diameter, thecircular plate being adapted for fixed attachment to and rotation by therotor plate of a common ceiling fan; such ceiling fan having its bladesremoved.

[0019] Upon removal of the fan blades of, for example, a common fourbladed ceiling fan, screw receiving fan blade attachment apertures ofthe ceiling fan's rotor plate are exposed. Typically, the lower surfaceof such rotor plate is elevated above the lower surface of the ceilingfan's motor housing. The upper circular plate of the present inventiveair filtering device preferably extends conically upward, such upwardextension terminating in a flattened circular upper end which is fittedfor attachment to the rotor plate of the ceiling fan. Screw receivingfilter attachment apertures are either drilled into or molded into theflattened upper end of the circular plate, such apertures beingpositioned and aligned so that they may underlie the fan bladeattachment apertures of the ceiling fan's rotor plate. Also, a lightfixture shaft aperture may be drilled or molded into such flattened openend. Such configuration of the upper circular plate and the filteringattachment apertures allows the air filtering device to be easily andconveniently attached to the rotor plate by means of screws or bolts.

[0020] A multiplicity of fan blades are fixedly attached to or molded asa part of the lower surface of the circular plate so that they extenddownwardly therefrom; the fan blades being radially configured andaligned in conformity with the common configuration of the blades of acentrifugal fan or pump. Upon operation of the ceiling fan motor torotate the upper circular plate along with the blades extendingtherefrom, the blades centrifugally accelerate air outwardly in allradial directions.

[0021] Lower structural support of the blades is preferably provided byan annular ring which is molded as a part of or fixedly attached to thelower outside corners of the blades. Preferably, the annular ringpresents an outwardly facing peripheral surface extending annularlyaround the outer edges of the fan blades. The outwardly facingperipheral surface preferably has a snap ridge receiving channelextending annularly therearound; the snap ridge receiving channelserving the function of securely and interchangeably holding acylindrical air filter retaining frame containing an air filteringmedium.

[0022] The air filter retaining frame preferably comprises a plasticdownwardly opening U-channel ring, and a plastic upwardly openingU-channel ring, the U-channel rings preferably being interconnected by apair of concentric cylindrical wire mesh walls. Preferably, the upperand lower edges of the wire mesh walls are respectively embedded withinand held by the lower and upper surfaces of the U-channel rings. Thecombination of the upper and lower U-channel rings, and the concentricwire mesh walls define a cylindrical filtering medium retaining andsupporting space. Within such space, any of several air filtering mediamay be deposited. Suitable air filtering media which may be depositedwithin such cylindrical space are activated charcoal, a pleatedfiberglass mesh, pleated woven fabric filters either chemically treatedor impregnated with activated charcoal, high efficiency particlearresting (HEPA) filters, or continuations of such filtering media.

[0023] A snap ridge is preferably molded as a part of the lowerU-channel ring so that the snap ridge extends inwardly from such ring'sinwardly facing surface. Preferably, the filter retaining frame isclosely fitted to the fan blades so that it may be slidably mounted overthe outer edges of the fan blades, and so that it may be manuallypressed into place, causing the snap ridge to snap into place within thesnap ridge receiving channel of the annular ring. Removal andreplacement of the air filter retaining frame is convenientlyaccomplished by manually pulling the air filter retaining framedownwardly, away from the blades, causing such frame to slide away fromthe fan blades. An opposite upward sliding motion imposed upon a new airfiltering frame containing a fresh air filter medium replaces theremoved air filter retaining frame.

[0024] In operation, upon rotation of the assembled air filtering deviceby the motor of a ceiling fan, air is drawn upward into the interiorspace of the air filtering device, and the air is centrifugallyaccelerated outward in all radial directions by the fan blades. The airthen flows through the air filter retaining frame and through the airfiltering medium contained therein. Such flow of air accomplishedcontinuous and noiseless filtration of the air, and accomplishesdesirable air circulation.

[0025] In the alternative embodiments of the air filtering device, theair filtering media is held between an upper plate coupled with therotary motor and a cover. The filtering media compartment orcompartments are further defined by the fan blades forcing air throughthe media and removable doors on the outside of the media near theperiphery of the device. In one alternative embodiment, the doors areslidably received within slits positioned around the periphery of theplate. In the other embodiment, the doors are pivotably connected to thedevice at spacers securing the cover to the plate. Furthermore, in thealternative embodiments, the blades are progressively curved so that theangle of the blades is more tangential at the inner edge than the outeredge of each blade.

[0026] Accordingly, it is an object of the present invention to providean air filtering device which is readily installable upon the rotorplate of a common ceiling fan; such ceiling fan having its fan bladesremoved.

[0027] It is a further object of the present invention to provide suchan air filtering device which utilizes centrifugal fan blades foraccelerating the air.

[0028] It is a further object of the present invention to provide suchan air filtering device further having an air filter retaining framecontaining an air filtering medium, such frame being annularly mountedaround the outer periphery of the centrifugal fan blades.

[0029] It is a further object of the present invention to provide suchan air filtering device further providing a snap ridge and a snap ridgereceiving channel for easy installation, removal, and replacement of theair filter retaining frame.

[0030] It is a further object of the present invention to provide suchan air filtering device which is economically constructed, and which isquiet in operation.

[0031] It is a further object of the invention to provide an airfiltering device having filtering media compartments between the upperplate and lower cover that remove particulates from the air.

[0032] It is a further object of the present invention to provide an airfiltering device with doors covering the air filtering media that areeasy to open and secure to replace the filtering media.

[0033] A still further object of the present invention is to provide anair filtering device that moves a large quantity of air and has greatdurability for filtering air laden with destructive properties inindustrial environments.

[0034] A further object of the invention is to provide an air filteringdevice that forces air through the filtering media at high enoughvelocity to use a variety of types of filtering media.

[0035] Another object of the present invention is to provide an airfiltering device having a plurality of centrifugal fan blades shaped topull air axially towards the device and through the filtering media.

[0036] Other and further objects, benefits, and advantages of thepresent inventive air filtering device will become known to thoseskilled in the art upon review of the Detailed Description whichfollows, and upon review of the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The objects and features of the invention noted above areexplained in more detail with reference to the drawings, in which likereference numerals denote like elements, and in which:

[0038]FIG. 1 is an isometric view of the air filtering device, viewedfrom below.

[0039]FIG. 2 is an exploded isometric view of the air filtering device,viewed from below.

[0040]FIG. 3 is a partial sectional view of the air filtering device;the sectional plane being vertical, passing diameterally through thedevice.

[0041]FIG. 4 if a magnified view of a portion of FIG. 3.

[0042]FIG. 5 is a plan, partially sectional, view of the air filteringdevice, viewed from below; the plane of the section passing horizontallythrough such device.

[0043]FIG. 6 is a magnification of a portion of FIG. 5.

[0044]FIG. 7 is an isometric view of an alternative embodiment of an airfiltering device, viewed from below.

[0045]FIG. 8 is an isometric view of the air filtering device of FIG. 7,viewed from above.

[0046]FIG. 9 is an exploded, isometric view of the air filtering deviceof FIG. 7.

[0047]FIG. 10 is an isometric view of the cover of the air filteringdevice of FIG. 7, viewed from below.

[0048]FIG. 11 is an isometric view of the cover, viewed from above.

[0049]FIG. 12 is a top plan view of the cover.

[0050]FIG. 13 is an enlarged fragmentary view of a connector of thecover.

[0051]FIG. 14 is an isometric view of the plate of the air filteringdevice of FIG. 7, viewed from below.

[0052]FIG. 15 is an isometric view of the plate, viewed from above.

[0053]FIG. 16 is a bottom plan view of the plate demonstrating thecurvature of the blades of the device.

[0054]FIG. 17 is an enlarged fragmentary view of one of the legs of theplate.

[0055]FIG. 18 is a cross-sectional view of one of the legs of the platetaken along line 18-18 in FIG. 17.

[0056]FIG. 19 is a bottom plan view of the industrial air filteringdevice of the present invention.

[0057]FIG. 20 is a cross-sectional view of the industrial air filteringdevice.

[0058]FIG. 21 is a top plan view of the upper plate of the industrialair filtering device.

[0059]FIG. 22 is a top plan view of the lower ring of the industrial airfiltering device.

[0060]FIG. 23 is a side view of a door of the present invention in aflat, rolled position.

[0061]FIG. 24 is an enlarged fragmentary view of the hinged connectionbetween a door of the industrial air filtering device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0062] Referring now to the drawings, and in particular to FIG. 2, thefan blades of a common ceiling fan (not shown) are removed from theceiling fan's motor 20, exposing a ceiling fan rotor plate 21, and screwreceiving fan blade attachment apertures 22. A light fixture (not shown)attached to the ceiling fan is also removed, exposing a light fixtureattachment shaft 23. Upon removal of such light fixture and ceiling fanblades, the ceiling fan is ready for installation of the air filteringdevice which, referring to FIG. 1, is referred to generally as drawingelement 1.

[0063] Referring simultaneously to FIGS. 1 and 3, the upper circularplate 14 of the air filtering device 1 is preferably between three andfour feet in diameter. Preferably, the upper circular plate 14 extendsconically upward terminating in a flattened circular area 15, such areabeing fitted for flush mounting against, referring to FIG. 2, the rotorplate 21 of the ceiling fan. Referring to FIG. 3, the upward slope ofthe conical section may commence (as shown) at the outer periphery ofthe upper circular plate 14 or, alternately, such slope may commence atthe inner edges of the fan blades 12. The flattened circular area 15preferably has four screw receiving air filter attachment apertures 17and a central light fixture attachment aperture 16. Where the rotorplate 21 is adapted for attachment of five ceiling fan blades, five airfilter attachment apertures in a pentagonal configuration are utilized.Upon attachment of the circular plate 14 to, referring to FIG. 2, therotor plate 21, by means of screws passing through the screw receivingapertures 17 and 22, the circular plate 14 may be rotatably driven bythe ceiling fan motor 20. A light fixture (not shown) may be reinstalledupon the light fixture attachment shaft 23 which extends through thelight fixture receiving aperture 16.

[0064] Referring again to FIG. 1, thirty-four curved fan blades 12extend vertically downward from the lower surface of the upper circularplate 14. Depending upon the overall diameter of the air filteringdevice, a greater or a lesser number of fan blades may be utilized. Eachfan blade 12 is outwardly arcuately curved and is tilted in thedirection of normal rotation for added efficiency in radial accelerationof air.

[0065] Referring simultaneously to FIGS. 1 and 4, the lower outer edgesof the fan blades 12 are structurally supported by a support ring 18having an inwardly extending annular flange 13, the lower outer edges ofthe fan blades 12 preferably being homogeneously fused with the innersurfaces of the support ring 18, and fused with the inner surfaces ofthe support ring 18, and fused with the upper surface of the annularflange 13. Referring simultaneously to FIGS. 2 and 4, the outwardlyfacing peripheral surface of the support ring 18 preferably has a snapridge receiving channel 24 extending annularly therearound.

[0066] Referring to FIG. 1, drawing element 5 refers generally to an airfilter retaining frame containing a filtering medium. Referring to FIG.2, the snap ridge receiving channel 24 serves the function of holding inplace the air filter retaining frame and air filter 5. Referringsimultaneously to FIGS. 1 and 4, the air filter retaining frame and airfilter 5 comprise a downwardly opening U-channel ring 6 and an upwardlyopening U-channel ring 8. A pair of concentric air permeable wire grids7 and 9 span between and interconnect the U-channel rings 6 and 8; theU-channel rings 6 and 8 and the wire grids 7 and 9 defining an interiorcylindrical space for containing an air filtering medium 11. The airfiltering medium 11 as depicted is a pleated fiberglass mesh. Othersuitable air filtering media are: activated charcoal, pleated wovenfabric filters which are either chemically treated or impregnated withactivated charcoal, high efficiency particle arresting (HEPA) filters,or combinations of such filters.

[0067] Referring simultaneously to FIGS. 2 and 4, a snap ridge 10extends inwardly from the inwardly facing surface of the lower U-channelring 8, the snap ridge 10 being fitted for retention by the snap ridgereceiving channel 24.

[0068] Referring to FIG. 2, in operation of the air filtering device,the ceiling fan motor 20 is operated to rotate the upper circular plate14 and the fan blades 12 in a clockwise fashion. Upon such rotation, airis accelerated radially outward through the openings 19 between the fanblades 12. Referring to FIG. 1, the air then passes through the airfiltering retaining frame 5, and, referring to FIG. 6, through the airfiltering medium 11 contained therein. As the air passes through the airfiltering medium 11, the air is filtered and cleaned.

[0069] Preferably, the circular plate 14, the fan blades 12, the supportring 18, and the flange 13 are formed through a plastic injectionmolding process. Also preferably, referring to FIG. 4, the upper andlower U-channel rings 6 and 8 are formed through a plastic injectionmolding process.

[0070] Referring to FIG. 1, the air filtering device 1 providesadvantages of economy in construction. The circular plate 14, the fanblades 12, and the support ring 18 may be economically constructed frominjection molded plastic. The air filter retaining frame 5, along withfiltering media contained therein may be inexpensively constructedallowing for economic disposal and replacement. The air filtering device1 also economically saves power allowing a single electric motor toprovide room air flow and air filtration. The air filtering device 1further provides economy in space usage; taking up virtually no livingor working space where it is installed and used. The air filteringdevice 1 additionally enhances the overall atmosphere of a room where itis installed and used by circulating and filtering the air whilegenerating virtually no background noise.

[0071] Referring to FIGS. 7 and 8, an alternative embodiment of thepresent invention is shown and is designated generally by the numeral30. With reference to FIG. 9, the device 30 includes a cover 32, aplurality of segments of air filtering media 33, a plate 34 having aplurality of fan blades 36, and a number of doors 38. Preferably, theouter diameter of plate 34 and cover 32 is 29 inches.

[0072] As shown in FIG. 10, the cover 32 has an annular support ring 40and an upstanding flange 42 disposed around the outer peripheral edge ofthe ring. With reference to FIGS. 11 and 12, a circumferential supportridge 46 and a plurality of radially oriented support ribs 48 are formedon the annular support ring 40. The ribs 48 and ridge 46 areapproximately the same height as flange 42. The ribs 48 originate atflange 42 and terminate at the inner diameter of ring 40. Preferably,the ribs 48 are integrally formed with the support ridge 46 andintersect with the ridge at substantially normal angles. The supportridge and ribs provide strength and support to the cover without addingadditional weight to the device.

[0073] At the inner diameter of the ring 40, a decorative screen 50 iscoupled with ring 40 of the cover. The screen 50 is comprised of aplurality of spokes 52 extending from the inner diameter of the ridge 46and terminating at a hub 54. The screen 50 further includes a ring 56between the support ring 40 and the hub 54 that maintains the spokes 52at the proper position from one another. The spokes 52 are curvedinwardly toward the fan blades 36 and shaped to generally complement thethe shape of the blades as discussed fully below.

[0074] The spaces within screen 50 are relatively large with respect tothe width of the spokes 52, hub 54 and ring 56 and allow a large volumeof air to flow therethrough. In addition to the aesthetic appeal of thescreen, the screen also prevents objects such as human extremities orcleaning utensils from contacting the blades of the fan and causingdamage to both the fan and the object.

[0075] As best shown in FIG. 12, the cover 32 includes a number ofconnectors 58 spaced equally around the circumference of the number base44. In the preferred embodiment, the cover includes five connectors 58spaced at 72° intervals around ring 40. With reference to FIGS. 11 and13, each connector 58 includes a seat 60 and an upstanding plug 62. Seat60 is generally rectangular. A first rib 64 supports the seat 60 on oneside and the seat is supported on the opposite side by a pair of supportribs 66 originating at flange 42. Ridge 46 provides lateral support toeither side of the seat 60. Screw receiving apertures 67 are molded ineach seat at the point at which the seat is supported by first rib 64.The seat 60 and ribs 64 and 66 have the same height as the ribs 48 andridge 46 of the cover 32. The plug 62 is disposed within the areadefined by seat 60, ribs 66 and flange 42. The plug is comprised of aspine 68 and a pair of cross supports 70 extending roughly twice thedistance from ring 40 as the members of seat 60.

[0076] Preferably, cover 32 is injection molded from a polystyrenematerial, but may be formed by other manufacturing methods. Moreover,the specific design of the cover, particularly the screen, may bealtered without departing from the scope of the present invention.

[0077] With reference to FIGS. 9, 14 and 15, plate 34 of this embodimentis shaped to mate with the cover 32. The plate 34 has a number ofattachment legs 72 for securing the plate to the cover. With referenceto FIGS. 17 and 18, each leg 72 has a neck portion 78 and a pair ofopposing sidewalls 74 in parallel relation to one another. Each hollowleg 72 is defined at one end of the sidewalls 74 by the walls of a bore76 and at the opposing end by an end member 80 capping neck portion 78.End member 80 extends in either lateral direction and is slightly curvedto correspond to the curvature of the outer edge of cover 32. The neckportion 78 and end member 80 define a pair of slots 82 extending thelength of each leg.

[0078] The plate 34 is fixedly secured to the cover 32 by aligning thehollow interior of each leg 72 with the corresponding plug 62 upstandingfrom cover 32. The ends of spine 68 and cross supports 70 frictionallyengage the interior surface of hollow legs 72. When the plugs 62 areplaced within legs 72, bores 76 and apertures 67 are axially alignedwith one another. As shown in FIGS. 9, 13 and 18, each of a plurality ofscrews 84 is placed through the bore channel 76 and into the screwreceiving apertures 67 in cover 32, and are frictionally threaded withinapertures 67 to hold the cover and plate in film connection with oneanother.

[0079] As best shown in FIG. 16, each blade 36 has a first edge 81 at afirst distance from the center of the plate and a second edge 83 at asecond distance from the center so that the blades form a ring on theunderside of the plate. Preferably, the device has 20 blades. In thisembodiment, the angle of curvature of the blades 36 is more tangentiallyoriented with the center of the plate at each point nearer the axis ofrotation. The curvature is best illustrated at either end of the bladewith respect to radial lines at that point. At the inner end of theblade, the input angle φ, the angle of the blade at the initial end ofthe blade with respect to the radial line at that point, issignificantly less than the output angle θ, the angle of the blade atthe terminal end of the blade with respect to the radial line at thatpoint. Thus, as the blade angle more closely aligns with the radiallines, the blade is more tangential.

[0080] For example, if the device is used in conjunction with a 120volt, single phase, sixty cycle, half ampere, 60 watt ceiling fan motorrotating the device at 200 revolutions per minute, the preferred inputangle is about 84° and the preferred output angle is about 24°. Underthese conditions, the air velocity vector β; the direction of air flowat the outer edge of the device with respect to the radial line at thatpoint, is also about 84°. However, the fan blades move such asubstantial volume of air at low rotational speeds that the device iseffective without the need to optimize each parameter of the bladedesign for more powerful motors. Thus, since the air filtering device isso efficient, a universal air filtering device effective for all typesof residential ceiling fans may be configured according to inexpensiveand inefficient motors.

[0081] As opposed to the original embodiment, the height of each bladepreferably varies along the length of the blade. With reference to FIG.14, each blade 36 is tapered and slightly concave with respect to theaxis of rotation, along the inner portions of each blade. As the bladeextends outwardly, the height increases generally linearly at an angleof between 50° and 70° with respect to the plate surface. Before theradial midpoint of the blade, the blade has a convex transition areafrom the relatively steep angle of increase. After the transitionportion, each blade is slightly tapered as the blade extends to theouter edge of each blade. The decorative screen 50, described above,roughly corresponds to the shape of each blade and a small space isdefined between each blade 36 and the screen 50.

[0082] The shape of each blade 36 advantageously draws air toward theblades and redirects the air through the air filtering media.Specifically, the combination of the blade height and curvature of theprogressively curved blades also prevents the misdirection of air belowthe device and directs a greater volume of air through the filter sincemore air is forced toward the air filtering element by the portion ofthe blade closest to the air filtering media.

[0083] A retaining ledge 88 is located near the outer edge of the blades36 and a peripheral flange 92 is formed on the edge of the plate.Between each leg 72, a narrow slit 86 is formed circumferentially alongthe outer peripheral edge inside flange 92. A plurality of ribs 90 arelocated between the ledge 88 and the inner edge of the slit 86.

[0084] On the upper surface of the plate, a set of screw receivingapertures 93 are located. In the preferred embodiment, the plate iscoupled with the rotor plate (not shown) of a conventional ceiling fanmotor by a plurality of mounting arms 95 and screws 97. The location ofapertures and means for mounting the plate to the motor is discussed inU.S. patent application Ser. No. 09/226,979, herein incorporated byreference. The plate 34 also has a central aperture 85 for receiving alight fixture or other accessory. Furthermore, the upper surface ofplate 34 has a support ring 89 and a plurality of ribs 91 extending fromeither side of the ring. Like the cover, the plate and fan blades arepreferably injection molded from polystyrene or a similar material.

[0085] With respect to FIGS. 9 and 14, the filtering media 33 is dividedinto a number of sections corresponding to the number of legs 72. Whenthe cover 32 is attached to the plate 34, the filtering media is placedbetween the cover 32 and plate 34 near the outer edge 83 of each blade36. The filtering media rests on support ridge 46 and ribs 48 of cover32. Retaining ledge 88 on plate 34 prevents the media from moving intothe spaces between the blades 34. Once the filtering media 33 is placedin the proper position, one of the doors 38 is placed over the filteringmaterial. As described above, the type of filtering media used may varydepending on the environment in which the device is used. Typically, acarbon or HEPA filter is used.

[0086] With reference to FIG. 9, each door 38 has a screen 94, a collar96 and a flange 98. The screen includes a first set of larger openings100 and second set of smaller openings 102. The openings are preferablyrectangular and the through space defined by the openings is preferablyat least 68% of the surface area of the screen 94 of door 38. The doorsare also preferably injection molded from polystyrene or a similarthermoplastic material.

[0087] The narrow screen 94 is shaped for receipt within slit 86 ofplate 34. The edges of screen 94 are slidably received within opposingslots 82 positioned on the neck portion 78 of each leg 72. When thescreen is placed fully within the slots 82, the bottom of the screenrests on the cover 32 and the circumferential collar 96 rests on theupper surface of plate 34. Thus, in this embodiment of the air filteringdevice, the filtering media 33 maybe easily removed by grasping theflange 98 and pulling upwardly on each door to expose the cavity betweenthe cover 32 and plate 34 outside the blades 36.

[0088] The effectiveness of the air filtering device will be dictatedlargely by the power of the ceiling fan motor powering the device.However, the device allows the air to be cleaned efficiently atrelatively low rotation speeds due to the blade design and positioningof the filtering media on the outlet side of the forced air means. Forinstance, the air filtering device rotating at about 193 revolutions perminute and having a carbon filter media processed about 2962 cubic feetper minute of air and at about 220 revolutions per minute processed 3629cubic feet per minute of air. In another configuration, the device wasequipped with a HEPA filter and rotated at 200 revolutions per minute toprocess about 3219 cubic feet per minute of air and rotated at 239revolutions per minute to process about 2892 cubic feet per minute ofair. As seen by these examples, the air filtering device is effective atall typical speeds of residential fan motors.

[0089] With reference to FIGS. 20-24, an industrial embodiment of theair filtering device is generally designated by the numeral 110.Preferably, the device is approximately five feet in diameter andconstructed of durable components. The components of the device 30include an upper plate 112, a lower ring 114, a plurality of fan blades116, a number of sections of filtering media 118 and an equal number ofdoors 120.

[0090] With reference to FIGS. 20 and 21, the upper plate 112 isgenerally planar. The plate is preferably made from a low weightaluminum, but may also be formed from a number of other materials suchas stainless steel. The plate has a central aperture 122 and a number ofscrew receiving apertures 124 each spaced at an equal distance from thecenter of the plate and angularly equidistant from one another. In thepreferred embodiment, the portion of upper plate 112 having theapertures 124 is in contact with a rotor plate (not shown) coupled witha rotary motor (not shown). Screws (not shown) are placed through theupper plate 112 through screw receiving apertures 124 and are receivedwithin matching apertures in the rotor plate. Accordingly, the patternof the apertures is dictated by the apertures in the rotor plate.Alternatively, the upper plate may be secured to the rotor plate inaccordance with U.S. patent application Ser. No. 09/226,979, previouslyincorporated by reference.

[0091] The fan blades 116 are preferably formed from the same materialas the upper plate 112. The metal blades are machined separately fromthe upper plate and attached to the plate by welding the upper edge ofeach blade 116 to the lower surface of upper plate 112. The shape ofeach blade is similar to the shape of the blades in the embodimentdepicted in FIGS. 7-18 and described fully above. In the preferredembodiment, the greatest height of the blades is about four inches.

[0092] The blades 116 are attached to the upper plate 112 is an annulararrangement to define a central cylindrical space to allow the inflow ofair and an annular area at the periphery of the device 110 between theblades and the peripheral edge 130 of upper plate 112. Preferably, theblades are attached to the upper ring by welding or a similar process.

[0093] The lower ring 114 has an outer diameter roughly equal to upperplate 112. The inner ring overlaps a significant portion of the blades116 when the ring 114 is aligned with the upper plate 112. The ring isalso preferably formed from aluminum or a similar metal. A number ofspacers 132 are welded to the upper plate 112 at the area of the platebetween the peripheral edge 130 and the fan blades 116. In the preferredembodiment, four spacers are welded at equal distances from one another.The spacers are the same or slightly greater height than the fansblades. The ring 114 is welded to the opposing end of spacers 132. Whenthe ring 114 is welded into place, a compartment is defined between theplate 112, ring 114, and fan blades 116.

[0094] The filtering media 118 is placed within this compartment. In thepreferred embodiment, the filtering media is a two-ply material having afirst layer 134 of a polyester filter and a second layer 136 of anactivated charcoal material. However, the filtering media may varyaccording to the type of indoor air environment in which the fan islocated.

[0095] With reference to FIGS. 19 and 24, on the open end of eachU-shaped spacer 132, a door mount 138 is secured. The door mount isplate-like and extends over the entire length of the open portion ofspacer 132. On one side of the door mount 138, an aperture 140 isdrilled at the vertical midpoint of the mount. On the other horizontalside of mount 136, the first flap 142 of a hinge 144 is secured to themount. Preferably, the flap is welded to the mount. The second flap 146of hinge 144 overlies the first flap 142 and may be pivoted away fromthe flap. The second flap 146 is welded to the first end 148 of door120.

[0096] With reference to FIG. 23, the door 120 is shown in greaterdetail. In the preferred embodiment, each door 120 has a number ofspaces 147 formed between first end 148 and second end 150 to allow airto flow freely from the device 110. The doors are also made fromaluminum or stainless steel in the preferred embodiment. An aperture 152is placed within the door 120 at second end 150.

[0097] With reference to FIGS. 19 and 24, the door 120 rotates aboutfirst end 148 at hinge 144. The opposing end 150 overlaps the door mount138 of the adjacent spacer 132 so that apertures 140 of the mount andaperture 152 of the door align with one another. A wing nut 154 isplaced within the apertures and threaded through a boss 156 positionedon the opposite side of door mount 136. A number of other fasteners maybe used that allow the door to be quickly secured or unsecured when thefiltering media is changed. For instance, devices utilizing springloaded knobs that are opened by depressing and swiveling the knob may beused.

[0098] The industrial model moves a larger volume of air and may be usedin a number of industrial environments. For instance, the device isparticularly effective to remove fumes from cleaning solvents,hydrocarbons, acids and paint. Moreover, the device may be used inwelding shops to remove dangerous particulates from the air surroundingthe workers.

[0099] While the principles of the invention have been made clear in theabove illustrative embodiment, those skilled in the art may makemodifications in the structure, arrangement, portions and components ofthe invention without departing from those principles. Accordingly, itis intended that the description and drawings be interpreted asillustrative only, and not in any limiting sense, and it is intendedthat the invention be given a scope commensurate with the appendedclaims.

What is claimed is:
 1. A ceiling fan comprising: a rotating motor; aplate coupled with said motor, said plate having a first side, a secondside, a center and a peripheral edge, said first side directed towardsaid motor, said second side directed away from said motor; a filteringmedia disposed proximate said peripheral edge of said plate, and aplurality of curved fan blades coupled with and extending away from saidsecond side of said plate, said blades annularly disposed to define acentral opening between the blades wherein air is pulled toward saidblades and directed through the filtering media.
 2. The ceiling fan ofclaim 1 wherein each said blade has an inner edge and an outer edge,each said inner edge at a first distance from said center of said plate,each said outer edge at a second distance from said plate, said seconddistance greater than said first distance.
 3. The ceiling fan of claim 2wherein the each blade is more tangential with at said inner edge ofsaid blade than at the outer edge of said blade.
 4. The ceiling fan ofclaim 3 wherein the height of each said blade is greater at said outeredge than at said inner edge.
 5. The ceiling fan of claim 1 furthercomprising a cover coupled with said plate to define a space whereinsaid filtering media and a portion of said blades are disposed.
 6. Theceiling fan of claim 5 further comprising a plurality of doors, saiddoors coupled with said plate at said peripheral edge, said doorsmaintaining said filtering media between said plate and said cover whensaid motor is rotating.
 7. The ceiling fan of claim 6 wherein said doorshave a plurality of spaces allowing fluid to flow therethrough.
 8. Theceiling fan of claim 7 wherein said plate has a slot formed along aportion of said peripheral edge wherein at least one of said doors issidably received within said slot.
 9. The ceiling fan of claim 7 whereinat least one of said doors is pivotally mounted to said plate.
 10. Theceiling fan of claim 5 wherein said plate has a plurality of legsextending from said second side near said periphery, each leg having ahollow interior and wherein said cover has a plurality of plugsupstanding from said plate, each said plug shaped to fit within saidhollow interior of said leg wherein said plugs are placed within saidlegs to secure said cover to said plate.
 11. A ceiling fan comprising: acircular plate having a peripheral edge, said plate having a pluralityof fan blades extending therefrom, said fan blades having an inner edgeand an outer edge, said outer edge of each blade positioned at adistance from said peripheral edge of said plate so that said fan bladesare arranged in a ring shape, said inner edges of said blades definingan inlet space, said plate further having a number of spacers extendingtherefrom; a lower ring having an peripheral edge, said ring coupledwith said plate at said spacers; at least one section of filtering medialocated between said plate and said ring, said section positionedproximate said peripheral edges of said plate and said ring, and atleast one door coupled with said plate and said ring proximate at saidperipheral edges wherein air is pulled toward said inlet space andthrough said filtering media when said device is rotated.
 12. Theceiling fan of claim 11 wherein the each blade is more tangential atsaid inner edge of said blade than at the outer edge of said blade. 13.The ceiling fan of claim 12 wherein the height of each said blade isgreater at said outer edge than at said inner edge.
 14. The ceiling fanof claim 11 wherein said door is pivotably coupled with plate and saidring.